US1716208A - Automatic train-control apparatus - Google Patents

Description

June 4, 1929. P. J. CLIFFORD AUTOMATIC TRAIN CON'IROL APPARATUS 12 Sheets-Sheet 1 Original Filed 001;. 22, 1923 Jnuenior:

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AUTOMATIC TRAIN CONTROL APPARATUS I Original Filed Oct. 22, 1923 12 Sheets-Sheet 3 June 4, 1929 P. J. CLIFFORD AUTOMATIC TRAIN CONTROL APPARATUS "Original Filed Oct. 22, 1923 12 Sheets-Sheet 3 v E wv and,

June 4, 1929. P. J. CLIFFORD AUTOMATIC TRAIN CONTROL APPARATUS Original Filed Oct. 22, 1923 I v -r mm '5 I 12 Sheets-Sheet 4 m 4, 1929- P. .1. CLIFF 0RD 1,716,208

AUTOMATIC TRAIN CONTROL APPARATUS Original Filed Oct. 22, '1923 12 Sheets-Sheet 5 W 9 pi T0030 3 if? LAY S HIGH SPEED ADVA/VCE CAUTION BLOCK ficuenior:

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AUTOMATIC TRAIN CONTROL APPARATUS June 4, 1929.

Original Filed Oct. 22, 1923 12 Sheets-Sheet 6 -E I PR :5 P

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P. J. CLIFFORD 1,716,208

AUTOMATIC 'TRAIN CONTROL APPARATUS- 12 Sheets-Sheet 8 June 4, 1929.

Original Filed Oct. 22, 1923 50 Jay.

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AUTOMATIC TRAIN CONTROL APPARATUS Original Filed Oct. 22, 1925 12 Sheets-Sheet 9 June 4, 1929. P. J. CLIFFORD 1,716,208

I I AUTOMATIC TRAIN CONTROL APPARATUS Original Filed Oct. 22, 1923 12 Sheets-Sheet 10 l/Zc June 4, 1929. P. J. CLIFFORD 1,716,208

AUTOMATIC TRAIN CONTROL APPARATUS Original Filed Oct. 22, 1925 12 Sheets-Sheet 11 S r E 1 35 31.

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June 4, 1929. P. J. CLIFFORD 1,716,208

AUTOMATIC TRAIN CONTROL APPARATUS Original Filed Oct. 22, 1923 12 Sheets-Sheet l? 514-0144 foz Fatented June 4, 1929.

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PATRICK J. CLIFFORD, OFFALLS,PENNSYLVANIA, ASSIGNOR' T0 rnArnconrnon CORPORATION OF AMERICA, 01? NEW YORK, N. Y., A CORPORATION on Costa WARE. I

. AFTQMATIC TRAIN-CONTROL APPARATUS.

Application filed October 22, 1923, Serial No. 670,123. Renewed January 12, 1928.,

One object of the invention is to provide an automatic train control system which operates to insure safetyot' the train when prescribed advance conditions. exist. p

Figures 1 to 5 of the accompanylng diagrams show the air system installed on the engine, and the new valves belonging to that system. r v

Figs. 6, 7 and 8 relate tothemeans for preventing the engineers disablmg valve from being operated back to IIOIIIIEIl'POSfElOD until the train has stopped, and for. convenience I have styled this,. a disabling valve lock DVL. I f

Figs. 9 to 14 show the electric relay system, distance control relay, and wiring on the engine, these diagrams illustrating the system under different trafiic conditions and difierent speeds of travel. The live. circuits in each diagram are indicated by the heavy lines, except the circuit, which is ener ized by the tachometer and includes the t reespeed relays.

Fig. 15 shows a circuit breaker to secure an automatic brake application if the shaft valve 19*.-

ot' the tachometer breaks.

Fig. 16 is a modified form of valve mechanism. I

i Fig. 16" is a sectional view taken vertically through the shaft of arm 15 of Fig. 16 show} ing details relating, 'to the engineers disabling valve. Fig. 17 is a view disabling valve lock. 7

Figs. 18, 19 and 20 are diagrams of a mech anism for taking care of conditions arising from open track switches. I

.Fig. 21 is a detail. Fig. 22 shows the parts of Figs. 18 to 20 in the track circuit. 1

Fig. 23 is a diagrammatic View of the primary relay PR which is mounted on the ve hicle.

ot a modified form of.

Fig. 24 is a diagrammatic view of the track circuits.

One object of the valve organization herein described is to simplify the construction, do away with the so called trigger valve used heretofore in the Glifi'ord system, and to operate the valve members by air pressure in both directions, thus avoiding the useo'f springs. v i

The valve mechanism maybe assembled in one unit to economize space,

' to gradually movet-he valve towards the right to open the exhaust. port 44, and it has a piston 46 which receives air pressure in the chamber46 through a port 46 by which this valve is automatically restored-to closed position, andwithoutthe use of-a spring.

7 The supply'ot operative air to thepiston- 46 of valve organization A is controlled by a valve EAV which normally closes a small; portto which equalizing reservoir air pressure is led through a pipe '39. This EAV valve closes against this pressure and the port is comparatively small, so that the valve can be'ma-intained seated by the energized solenoid coil 30, which-is controlled by the electric relay mechanism onthe engine. The core of this solenoid is connected with the EAV valve, and thiscore also carries a When the solenoid S0 is 'deenergized, the. EAV is opened by the incomingair pressure (equalizing reservoir) and air goesv through port 22v topact against. piston 46 to open the exhaust port 44'. When the EAV valveis opened, the valve 19* at the same time is set, to connect the passage 46? with a small-exhaust port 22". for theoutlet of air from the.

right hand side of the valve organization A, i. e., from the piston chamber 46. .The valve 41 will move to the right gradually. under the pressure of air let in through port, 22 and under the resistance or control of the air exhausting gradually from the piston chamber 46 through passage 46 and restricted exhaust port 22". A gradual train pipe reduction will result and the brakes'willbe set without or shock. ,Now when the solenoid'is, again energized (which will take place when the speed of the train has been reduced to say 5 miles perhour), it will close the EAV valve against the pressure o'tthe air coming in through the small port from pipe 39, thus cutting ofi' further supply of air to the piston 46, and at the same time the valve 19 will be set in position to connectthe passage 46 with a port or passage 46Tleade ing-from the equalizing air pressure supply.

' beyond the valve EAV, so that this air pres sure is always available in said port 46*. As soon as these passages 46 and A6 are connected by the port 19? of valve 19 pressure is admitted to the right hand side of the valve organization A to act on the piston 46* and force the'valve 41, together with piston 46, leftward, to close the train line exhaust port 44. the valve 19 is set in the position just mentioned to supply air to the right of valveorganization A to move same to closed position the port 19 in the valve l9 connects the port 22" with the outlet port 22 to atmosphere for the escape of air pressurefrom the left hand side oi"; the piston at"), so that valve organization A,under pressure of the .air in chamber 46 can move leftward and close valve l1. Thus all parts are restored to 7 normal position again. 19 is a port to direct air to-equalize pressure on valve 19*.

It will be noted that there is no restoring spring employed either in connectionwith the-valve organization A or with the EAV valve and solenoid core. The solenoid core with EAV valve and valve 19 are moved in one direction, i. e., to closed position of EAV valve, by the energizing off the solenoid, and in the reverse or opening movement it is operated by the pressure of the equalizing air at the small. port where the'E AV valve is seated.

A piston 19 is arranged to receive the air pressure comingin through the EAV valve so as to move this valve organization to its open or retractedposition when the coil 30 is deenergized.

WVe have said above that the 'coil 30 is reenergized when the trains speed is reduced to 5 P. H. This is an example of one use of this valve mechanism, and will be understood that the solenoid may be reenergized at a different point in the sequence of train control. 'I mentioned the 5 M. P. H. point, as the engine equipment will include a contact which will close a current path tfor'reenergizing the solenoid when a safe low speed is reached. This'does not meanthat the train would not stop under automatic braking at speeds above 5 M. P. H., for, as a matter of fact, a lock is employed to hold an engineers disabling valve in closed position 7 when once set, so that the engineer can not recharge the train line and release the brakes until the train comes to a stop, whereupon the lock of this disabling" valve will be automatically .released, so that then the engineer may recharge the train line, release the brakes, and proceed again aft-er stopping, the solenoid already having been energized, as above stated, when the speed reached 5 M. P. H.

An important advantage accrues from the system above described in which the solenoid is reenergized and cuts ofi operative air to the At the same time that prevent" further train pipe reduction when the speed has come down to 5 M. P. H., be-

cause with such system we get a train pipe reduction commensurate 'with the speedof the train, due to the fact that the solenoid will not be reenergized until the trainhas been brought to 5 M. P. H. from the speed at which it is travelling at the point of automatic brake application. Obviously it the train is running at 60 M. P. H. when theautomatic braking takes place, it Will'take longer to get down to a safe speed of 5 M. P. H. than if the train is running at 40 M. 'P. H. when the automatic braking takes place. Consequently when running at 60 M. P. H. the train pipe reduction will continue for a longer period of time than if the train is running at 35 M. P. H. Thus the speed ofthe train determines automatically the degree of train pipe reduction, this being proportionate to the speed of. the train.

key B and arranged, when the shaft B turned, to open or close the opening in a sta- This valve is opertionary partition B ated by an arm B which in turn'is operated by a piston B", when this is moved leftward in Fig. 3. This piston is operatedleftward by equalizing air pressure let in through a port 51 from the chamber 15, in which the piston 46 operates, and the supply of air goes through this conduit as soon as the EAV valve opens. The piston B is normally held locked by a plunger B entering a notch in the piston. The first effect of the air enter ing through conduit 51 into the chanibeiilim is to supply air through port 51 and check valve 51' to space 51"" at the left of plunger B thus forcing this plunger or piston rightward till its groove B comes oppositethe plunger B whereupon said plunger is free to rise into said groove andrelease, the piston 13,

which then, under pressure of air in chamber notch B, and as soon as this happens the piston B will be moved leftward, owing to the air pressure entering through port 51 which pressure, added to that of the spring 13'' (which latter may be omitted), will'giv e the piston B the movement stated. This will Reverting to the valve action, I have probring the plain part of this piston over the locking plunger B and hold this down. The parts will beheld in this position with-the ene gineers automatic service valve (l/Vestinghouse H disabled until ressure has bled through port 57 as hereinafter described. This air pressure will through a check valve B to the left hand side of the piston B thus moving it to the right to bring the groove B thereof in line with locking plunger B so. that'the latter can rise and not obstruct the movement of piston 13 back to normal position, which happens because of the pressure of air exerted in the'chamber Ba supplied through port 57. This air finally exhausts through port 103. When the piston B is all the way towards the right, the plung er B drops into the notch B to lock the piston B in its normal position. Thereupon the piston B moveslelitward under action of its spring B A port Bp bleeds chamber 51" when B is rightward.

It will be seen that the only spring in the whole valve organization is the spring B which has light duty to perform. The disabling valve lock is shown in Figs. 1 and 6 to 8 at DVL. It is not applied directly to the engineers disabling valve, though this might be done. Instead it is applied to a valve D which cuts off communication between sections of pipe 57 leading TLOHL the main reservoir tothe conduit 57. D can be unseated to supply air pressure to conduit 57 for restoring the engineers disabling valve to normal open position by a hand lever D Butthis hand lever can not be operated until the train has come to a stop, because a lock 1) holds'the stem D locked and it is this stem which must be operated by I the handle D in order to unseat valve D and iii allow air to go to the disabling valvefor restoring it. This lock is controlled by a magnet D which, when the train is moving, is deenergized.

The energizing oi. magnet D and the consequent release of the disabling valve lock D of DVL to enable the engineer to restore the engineers disabling valve to'open position is dependent on two factors. 7

One of these is the closing of contact at D when the solenoid 30 is againenergized and the EAV has closed, consequent upon the train coming down to the prescribed low speed of 5 miles per hour, and the other factor is the closing of the tachometer pointer D on contact D when the train comes to a.

stop all as hereinafter described. lVhenthis This valve happens the brake solenoid 30 has been ene'r gized and so far as this is concerned the train is ready to proceed, excepting that the brakes have not yet been released.

The release the brakes is dependent upon restorin g the disabling valve to open position, so that the engineer can recharge the train line, but this can not be done'until after the train has come i-to a stop and tachometer pointer D has closed onto contact D I Fig. 17 shows another form of the disabling valve lock. Both of the contacts 1) The battery 01": this. circuit is shown at D for convenience of'illustration. This tachonr' and instead of the battery D the mainbattery may beused.

Engine electric equipment,

y and D are in the circuit of thetachometer and magnet .D

Theprincipal elements of the engine electrical equipment of the accompanying dia grams are: a primary relayPR to pick up current troin the traction rail or rails shown in Fig. 23; a brake solenoid 30-which when deenergized causes the brake I controlling means to make an automatietrain pipe re duction for applying the brakes; a distance control relay DR which includes a screw DS rotated by a flexible shaft from tlie'engine' axle; a nut N to engage said screw;.1nagnets having an armature a? pivoted at pi to drop,

leftward away from themagnets when the latter are deenergized, said armature having the nut N slidably mounted thereon, so that when the armature drops leftward from the deenergized magnets the nut will be made to engage the screw, which n-ut will therefore traverse the screw to its upper end where it hits a button on the rod 9 and-opens contact SO controlling one of the paths of the brake solenoid (30) current, There is also a high speed contact lbs and an advance high speed contact alts controlling one ofv the paths of the brake solenoid current and these contacts open when the armature of the primary relay is at neutral. There-is also a moderate speed relay MS, a low speed relay LS and a no speed relay OS, the'torqueot whose coils are, relatively regulated so that at a moderate speedof, say at or below35 miles per hour, the contact lot the MS relay will close. Thecontact 2 of the relay LS will close at or below 5 M. P.'H., and the contact 3 of relay OS will lie I close at zero speed,- i. e'., when the train comes to a stop. These relays are operated from a tachometer, driven from the axle of the engine. There is also the lock DVL for the engi'neers disabling valve controlled by the solenoid or magnet D a speed indicator ST and a light'SCL, which is lighted when. the train comes to a stop and which will checkthe operativeness of the relay circuit because i the green signal will be lighted, but if the train enters a dead block then the falling away of the armature will cause the contact G to engage contact strip 3 and light the yellow light as shown in Fig, 11, and as it travels with the nut the contact C will engage the strip 1 and the red light will go on the braking point is approached as shown in 13. There is also a lock LO which will prevent the engineer from exceeding a slow speed of, say 5 M. P. H. on entering an energized occupied block, excepting he gets an automaticbrake application, this locked condition persisting until there is a reversal of polarity of the current picked up by the primary relay consequent upon the train ahead get two blocks awayas will be described later. The primary relay PR Fig. 28 is of the Du Pre 'DArsonval type, its armature or pointer closing on its contact, on say, aotential above plus or minus 1.5 millivolt. This t pe of relay is like that made by Weston Electrical Instrument Co. of Newark, N. J. Model 30, and disclosed as to its general features in patents of the United States of Edward l Veston 'for instance, No. 611,722 Oct. 4, 1898 or No. 446,- 489'of Feb. 17, 1891.

The manner in which the polarity of the current is reversed is hereinafter described in connection with Fig. 24.

During high speed above, say 35 M. P. 11.,

in a clear block, Fig, 9, the contact CL and the high speed contact he. at the primary relay will be closed and the circuits will be established as follows one through contact CL, the retarded magnets of distance control relay DR, green light G, tominus of battery. The red and yellow lights will be out because sliding contact G willnot be in engagement with strip y, 1'. These retarded magrets and their function are later referred to.

A solenoid circuit will also be established from plus of battery through brake solenoid 30 (which will hold the brakemechanism inactive) through tachom'etersaiety contact TC, thence through contact SO, wire he to contact he, and from he, armature ot the primary relay, contact CL, to magnets of Dltrelayand thence to green light G and to minus of battery. From wirehsthe current must go to contact hs because at high speed contact '1 of relay MS is open. is long the magnets are energized, the nutN, which is slidably. mounted on the armature er of these magnets, will be held out of mesh with the constantly rotating screw DS and consequently will not traverse this screw, and the contacts controlled by this nut will not be changed from normal clear condition and the circuits will be indicated in Fig. 9.

High speed advance caution block-Fig; 10illust.rates the conditions when the train is in an advance caution block, i. e., the block on the approach side of the caution or dead block, or, to designate this advance block in another way, it is the second block in rear of the occupied block. a 1

When a train is in this advance caution block the puroose is to give the engineer an advance signal 'iidication notifying him that he is approaching a caution board. 'In this advance block the polarity of the current picked up from the traction rails is re-. versed in a manner set forth hereinafter in connection with 243-. I

Therefore, when the train enters this ad- Vance block, the ari'nature of the primary relay PR will its position :and en- "aee'the contacts Ad and advance hi 'h s )eed to Q! r 1 x tr: contact aizalhe magnets ct ,dlstance con- "-1 y n n 3 i X t y (l L10 relay ,lL sow acting so lat my will maintain armature a? picked up during the time the arm of the primary relay.

is swinging from contacts Gi aud he, to Ad and aka. The only changes, therefore, inwthe diagram of Fig. 10 over that of: Fig. 9 are (1) that the primary relay has reversed and has closed a circuit through the advance contacts Ad, and alas,

thus lighting the white light W, which pen cient to say that this lock under certain con-.

ditions will lock the armature or against beir picked up by the i'nagnets oi? the distance -ol relay DR, until a certain condition of tiaiiic has been reached.

High speed caution 5Z00k.l low ifthe train enters a dead block at high speed, as shown in diagram Fig. ll, the primary relay P 1 will to *al position break contact at Ad and CL, and (the, as, and magnets of DR relay will be deenergized and itl'll'llilillfi er will fall to the left, for purposes nicntioned later. As the brake solenoid circuit now depends upon the contact he or ("i/lie its maintenance at high speed, the solenoid 30 will be deenergized, and therefore the bral zes will be immediately applied because the deenergizing the solenoid will open the air valve, which controls the setting of the automatic air release valve for making a train pipe reduction.

When the brakes are applied the engineers I engineer, can not be restored to normal open.

leading from the mainv reservoir to the en-.

gineers automatic brake valve H, so that the engineer, while disabled from recharging the train pipe, can still make a faster train pipe reduction by manually operating his automatic brake valve.

The disabling valve, once it 15 set in position to disable the position again until the train has come to a stop, and for this purpose there is provided the automatic lock for the disabling valve, as previously described, to maintain it closed. This lock DVL is controlled by the magnet or solenoid D which may be energized through the contact 3 of the no speed relay OS, which contact closes only when the train comes to zero speed, i. e., a

stop. When this happens (the EAV valve having been closed and the circuit closed at D as above mentioned) the solenoid or magnet D is energized and releases the lock and thereupon the engineer can restore the disabling valve to normal. position either by sending air pressure from the independent brake valve S or through the special manually controlled valve D from the main reservoir, as previously described herein.

In the above example the yellow light Y will take the place oi the green light, as shown, because the contact C will engage the strip 1 when the armature a1" drops leftward. This contact is carried by the nut N, and this yellow light will be maintained while the contact C is traversing the contact strip 1 it being understood that when the armature (W falls leftward from the deenergized magnets the nut N is set into engagement with the constantly rotating screw DS and traverses this screw, carrying the contact C with it. This traversing action of the nut N under the example now being considered, will in a sense he an'idle movement, the main purpose of the screw coming into play under other conditions about to be described.

Caution bZ007c.Moderate speed of, say M. P. 1-1.: If train enters a dead block, Fig.

12, at a prescribed moderate speed of, say at or below 35 miles an hour, the 35 mile contact 1 of relay MS will be closed. High speed contacts its and alts will be open because armature of PR is at neutral, but the circuit through brake solenoid will be maintained through this 35 mile contact 1 until the circuit isbroken at S0 at the time the nut N has travelled to the top of the screw DS and operated rod 9 by striking the button there on. \Vhen this happens, i. e., the opening of the circuit at distance contact SO by the lifting of the rod g, the brake solenoid 30 will be deenergized and the brakes will be applied;

This braking action will take place at a ma s'onable braking 7 distance" from the home board, the length of the serewiDS being'such that the nut N will open the solenoid circuit at this predetermined distance from the be ginning of the caution block. LockLOwill maintain this conditioneven though the train runs into live territory, until the train ahead gets two blocks away.

Sig 1mZs.Now when the magnets of the DR relay become deenergized on entering the dead block and the nut has fallen-over onto the screw, the contact 0, which is attached to V v the nut, will engage the contact strip 51 so that the yellow light will come on at the same time that the green light goes out, and this yellow light will persist while the contact G is. crossing the insulated break between the contact strip 2 and the contact strip 1. When the contact C .is straddling this insulated break, the yellow light and the'red light will 1 be on at the same time, but as soon as the contact slide O gets entirely on the strip 1', then the red light will persist alone, and this happens just before the braking point is reached, so that, the engineer will be notified that he is approaching the point of automatic appli cation and in order to continue must reduce his speed to 5 M. P. H. j

Under the conditions" just described, like in the case above described, once the solenoid 30 is deenergized, the engineers disabling valve is set so as toprevent the engineer from rechargmg the train pipe and the train must come to a stop.

Fig. 12 shows that the engine has entered the caution block at moderate speed and is proceeding to the point in said block where the brakes will be applied automatically, if the engineer takes no action. The nut N is in course. of travelling along the screw DS and the solenoid 30 remains energized despite the 'factthat the high speed contact its is broken. the solenoid circuit being maintained through contact 1 of the moderate speed relay MS, and this condition will persist until the nut N reaches the upper end of its travel and breaks contact at SO by lifting the rod 9, whereupon the brakes will be applied automatically by the deenergizing of the solenoid 30.

Starting up again in dead bZ0c7a.Under either of the above conditions after the train has come to a stop it can be started again beand thiscircuit is maintained when the trainhas come to a stop because the relayLS will have its contact closed at all speeds from 5 M. P. H; to zero. I

We would then have a condition'in which the train is at rest, solenoid 80 is energized,

'contact'D made, and consequently the air brake controlling mechanism is restored to normal position again, and because the train is at rest and contact 3 closed the engineefis disabling valve lock is released and the engineer can restore this valve to normal open position, and thereafter he can recharge the train line and release the brakes.

He can proceed at low speed, i. e., below 5 M. P. H. Should he exceed this speed in the dead block, the low speedrelay LS will open its contact 2 .and thus the circuit of the brake solenoid will be broken at this point and an I automatic. brake application will result.

Slow speed in dead bZ0cla.Should the engineer enter the dead block at a prescribed safe low speed, say at or below 5 M. P. H. (see Fig.'13), the contact 2 of the low speed relay LS is closed and the circuit through the brake solenoid 30 will be maintained and the brakesprovided to hold the engineer down to a'safe low speed upon resuming travel in a dead block after a stop, or on entering a dead block at, say a safe speed of 5 M.'P. H., or

on'entering an energized or occupied block,

I as indicated in Fig. 14,- said lock being released only when the train ahead gets two blocks away, or into a position bringing on the condition of an advance caution block, above mentioned.

For this purpose the lock L0 is provided, which will drop behind the armature m" of the relay DR as soon as this assumes its position away from the magnets, due to these magnets being deenergized. This lock will prevent the armature from being picked up again by these magnets until the train in advance gets two blocks away, when, due to the reverse polarity of the current received by the primary relay, Fig. 10, as described hereinafter in connection with Fig. 24, the armature of this primary relay PR will engage the advance contact Ad and energize magnet Lm and raise the lock L0 and thus permit the magnets'of relay DR to pick up their armature, and cause the nut N to drop, by withdrawing it from the shoulder at the upper end of the screw DS upon which it has been resting. The dropping of the nut will allow contact S0 to close. It will thus be seen that the train having entered a dead block, and the armature of relay DR having been locked in itsdropped position, the circuit of the solenoid is controlled entirely by the contact 2 of low speed magnet LS, and even though the train enters a live block the'speed can not exceed 5 M. P. H. in that live block, because it requires a current of reverse polarity to release the lock LO and this can not happen until the train ahead gets two blocks away from the following train. '01 course the same locking etl'ect will take place on the engine entering a dead block at or below 5 M. P. H. This engine must proceedat this low speed,

else stop will result, until the train ahead gets two blocks away.

lVhile the train is in the occupied block, i. e., live territory, under the above cond1tion i. e. at a speed below 5 M. P. 11., the red and In Fig. 16 I show a valve organization in which the automatic air release valve A of the previously described organization is omitted, and in this new organization I employ only the solenoid actuated valve EAV and the engineers disabling valve B in combination therewith.

V hen the valve EAV is seated by the energized solenoid coil 30, equalizing reservoir air pressure is cut off from this new valve organization and conversely air is supplied to said valve organization upon the opening of the EAV valve, due to the deenergizing of its coil 30; When the EAV valve is closed, the engineers disabling valve may be either in normal open position, or in closed applied position, that is to say, under certain conditions the valve EAV may close, while the disabling valve is still performing its function of'disabling the engineer from recharging the train line and releasing the brakes.

The engineers disabling valve is shown in Figs. 16 and 16. Its port 51 receives equalizing reservoir pressure through the space 19 of the valve 19 from the passage sli -when the EAV valve opens and moves the valve 15) to its retracted position, and the disabling valve, as above described, is thereby set in closed position to disable the engineer 'lPom recharging the train line. i

In the closed position of the EAV valve the port 19 in valve member 19 connects passagefil with the supplemental exhaust port 22 leading to atmosphere, so that in restoring the engineers disabling valve to open position,-air pressure will be discharged through this port from the right hand side of the piston B. 2

Assuming the train is travelling ata high rate of speed and is approaching a clear in I sume that he does not do this and passes the caution indication point at this high rate of speed, the following operation of the valve organization of Fig. 16 Will take place: The coil 30 of the EAV valve Will be deenergizec and equalizing air pressure in pipe 39 will force EAV open and cause piston 19 to travel. This in turn Will cause ports 16" and 51 to be brought into communication with each other by movement of valve 19, and as a result of this, arm 13 of the disabling valve B Will be forced leftward to cut off all connection between the niain'reservoir and the usual air brake system, such as Nestingllouse, and thus render the train line incapable of being recharged.

In continuity With this action the piston 19 continuing its travel uncovers port 22", allowing pressure in chamber D and equalizing reservoir (l l estinghouse) to exhaust to the atmosphere.

The reduction of pressure in chamber D of the engineers big brake valve (as H lVestinghouse) will allov-n the equalizii ton to be forced upward by brake pipe 1 I,

sure beneath it, opening the usual l: EX. and thus reducing train line pressure and causing an automatic application of the brakes.

This condition will persist until the speed of the train has been brought down to, say 5 M. P. H., when the 5 mile contact of relay LS will close, reenergizing coil 30 of the EAV valve, thus closing this valve and leaving the brakes in a complete lapped condition, port 22 being closed and the disabling valve B being also closed.

Train line air Will continue to exhaust through E. P. EX. until its pressure has fallen to an amount a trifle less than that contained in chamber D, permitting the pressure in this chamber to force the piston downward gradually and stop the discharge of brake pipe air. t will be seen therefore that the amount of reduction in the equalizing reservoir determines that in the brake pipe, regardless of the length of the train.

The disabling valve 13 now is in closed or applied position and can not be restored to normal or open position until the train has been brought to a stop, and, as before described, air pressure has been sent througl'i port 57 of the disabling valve, restoring the ire-sdisabling valve to normal open position, so

that then the engineer an recharge the train line and release the brakes.

It Wlll be seen that the amount ofbrake application in this form, as in the form first described, will be determined by the speed of the train; the higher thespeed the greater the train pipe reduction in coming down-to a speed of 5 miles per hour.

The primary relay PR is in a conductor re-, ceiving current from the traction rail system, due to the potential drop between its points of contact therewith. This primary. relay is in continuous conductive connection With the electrical track system.

AtTc, Fig. 15, I provide a safety device Whichwill bring on an automatic brake application: by breaking the circuit of the solenoid 30, should the shaft of the-tachon'ieter break. If this happens, alspring' 7 will force the slidable contact f5 from normal position and thus break the said circuit.

1 do not limit myself to the specific organizations described. Thespecification and devscription are presented as lllustrative ofn'iy invention and not restrictive upon its scope which is defined by the appended clanns. I

The re-energizing of the solenoid 30 may take place at a different point in respect to the. movement of the train than that mentioned.

The distance control'relay DR will stop a train in a dead block at a prescribed distance after passing the caution signal, regardless of its speed or the number'of mtermediate stops it may make, so long as the block remains dead.

in all the Figures 11,12, 13, 14, the lock LO Will persist and prevent dropping of the rod q and closing ofcontact So even though the train runs into an occupied block and ener gizes magnets DR. These conditions Will persist until the trainahead gets two blocks away and the polarity of the current changes. This change of polarity is obtained in a manner disclosed in Fig. 2d hereinafter referred to. Features of the invention are not restricted to the character ofthe electriccurrent'emplayed. l

. In Figs. Wand 13 TSllOW means associated with the tachometer circuit for taking care of conditions arising from failure of this circuit by breakage. In these figures a relay SUB has its magnet in series with the mag-v nets of relays OS and MS. Its contact is in the common Wire leading to minus of main battery D g The low speed relay-LS has its magnet in a circuit of 1ts own energ zed by the tachom- (3 i(31',311(ltl18 contactof this relay also controls, the circuit through the common Wire leading to minus of the battery D 1 SGB opens its contact below 5 M. 'P, H.,

and LS closes its contact below 5' M. P. H.

Diagram 9 represents high speed conditions in a clear block. In this diagram the solenoid circuit breaker SCB will come into play if for any reason the track circuit fails with the tachometer circuit in broken condition. Under these circumstances, and supposing SCB were not present in the system, we would still have the solenoid circuit maintained through contact '1 and the brakes would be held in released condition despite the fact that the primary relay had assumed neutral position. ith the circuit breaker SUB in the system, however, we would get a break in the solenoid circuit at SOB, at this high speed (low speed contact 2 being open), the moment that the tachometer circuit accidentally broke, with a brake application consequent upon deenergizing of the solenoid 30, the primary relay PR having assumed neutral position as a result of the failure of the track circuit. It will be noted too that low speed contact 2 of the LS relay will be open at the same time that the contact of S013 is open, for the reason. that we are considering the high speed condition and under thiscon-v dition contact 2 is open. It closes only when the speed is low,'say 5 P. H.

Now supposing the circuit in which the magnet of the low speed relay LS is located broke simultaneously with the breaking of the main tachometer circuit in which the magnet of SOB is located, we would still get a break in the solenoid circuit, despite the fact that the contact 2 of the relay would close,

because the closing of this contact is delayed,

and it does not close until after the contact of S013 has opened and broken the solenoid circuit. For this purpose the magnet controlling low speed contact 2 is retarded in its drop away in respect to the drop away of magnet SOB, so that even though the circuit of low speed relay LS should break simulta neously with that of SOB, the contact 2 would not close until SCB had been open long enough to deenergize the solenoid 30 and apply the brakes. When contact 2 closes the solenoid 30 would be energized again, and even though the brake pipe reduction up to this moment has not been suflicient to stop the train, a sequence of actions has been started which will accomplish this result. This will be due to the followin When the PR relay assumed neutral position the magnets of the relay DR were deenergized and nut N began its upward travel and thus after the predetermined distance has been traversed by the train, the contact SO will open and the solenoid will be deenergized again and the brakes will go on for a secondary application. This second braking action will definitely indicate to the engineer that his tachometer circuit is in broken condition.

Now in order to reenergize the brake solenoid so that the engineer can proceed after a stop, I have provided another contact SO which is closed when the nut N reaches its upper limit. The solenoid 30 is retarded in becommg (lo-energized so that when the nut N and rod Q fall down to their starting position, the consequent momentary open positien of the circuit at'SO, S0 will not result in dceuergizing the solenoid, and hence there will be no automatic brake application while the armature of SO is rapidly moving down circuit at SCB counteracts the closing of the,

solenoid circuit at 1, consequent upon the rupture of the tachometer circuit.

Below 5 Ill. P. H. in caution b20073, mm.- ning wth brakes (z ;12pZiecZ.-Diagram 13 illustrates this condition in a system like that described above in connection with ig. 9 In this diagram 13, magnet of SCB is designed to allow its contact to open at a speed below 5 M. P. H. Contact of the low speed relay LS closes at said speed. Medium speed contact 1 is closed. This diagram shows the conditions below 5 M. P. H. in a caution block, with the brakes applied but with the train still running but about to be brought to a stop at the red board. Here the nut N has near y, though not quite, reached the upper limit of its travel and the contact SO has assumed an open position about midway between its front and back contacts. The sole-- noid circuit is therefore broken at SO and the brakes are applied.

Nut N, continuing its upward movement, closes front contact S0 and because con tacts 1 and 2 are also closed the solenoid circuit is reestablished. The train will come to a stop, however, because disabling valve lock will not be released and the engineer can not recharge the train line until the full stop has taken place.

The train is now ready to be started. again, owing to the reenergizing of the solenoid as just stated, by reason of front contact SO being closed, and the engineer can proceed into the occupied block, but only under restrictive speed, sayof 5 M. .P. H, or below. Should he exceed thisspeed, con tact 2- will open quickly because itscoil is of the quick pick-up type and slow drop away. The magnet of SOB is slow pick-up and quick drop away, so that with a speed above 5 P. 11., we would get a break of the solenoid circuit at this point. i

From the above it will be seen that the apparatus makes it mandatory that all signal

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